Hodgepodge Machine (BZ Reaction)

This Cellular Automaton models the Belousov-Zhabotinsky (BZ) chemical reaction, creating expanding concentric rings and spiral waves out of a chaotic soup (a "hodgepodge").
Cells can be Healthy (0), Infected (1 to N-1), or Ill (N).
Healthy cells get infected based on ill neighbors. Infected cells get sicker based on neighboring infection levels plus an internal rate. Ill cells instantly become Healthy again. These three simple rules give rise to macro-scale, pulsating, self-sustaining chemical clocks.